Walt Disney's Zootopia is an unlikely success. In a year in which the celebrated animation studio will release a long-awaited Pixar sequel (Finding Dory) and introduce a new Disney princess (Moana), a quirky film about talking animals running around in tiny clothes — a personal favorite genre of Disney Animation Studios chief John Lasseter — seemed destined to be forgotten by summer. And yet, it's not only on the cusp of crossing the $1 billion mark at the worldwide box office, but it's also spawned the most fervent internet fandom this side of Supernatural.

In fact, Zootopia is currently the #2 movie fandom on Tumblr, behind Captain America: Civil War, according to Tumblr's Fandometrics — and that's nearly three months after its theatrical release.

It's easy to see why audiences fell in love with Zootopia. Directors Byron Howard (Tangled) and Rich Moore (Wreck-It Ralph), along with co-director Jared Bush, know how to keep things light. It's a quirky buddy-cop film starring a plucky rookie officer and a sly, small-time con artist ... who just so happen to be a bunny and a fox, respectively. They live in a place called Zootopia, a booming metropolis where predators and prey live in near-harmony. This world is colorful and expansive. (It's so huge, Howard called it "the most complex movie and world that we've ever created at Disney.") And in Zootopia, sloths work at the DMV — what's not to love about that?

However, beyond its bright and bouncy tone, Zootopia cuts deep, as it ambitiously tackles the thorny issues of prejudice and profiling through the inter-species friendship of its furry protagonists, Judy Hopps (bunny) and Nick Wilde (fox). For example, Judy describes Nick as "articulate," and, later, patiently explains, "A bunny can call another bunny 'cute,'" but someone who's not a bunny can't. With its potent feminism and invaluable lessons of tolerance, Zootopia is a film that takes chances and refuses to play it safe.

"You hope when you're working on these things that people love them, whether it makes a lot of money or not," Howard told MTV News while promoting the June 7 DVD and Blu-ray release of the film. "We want these movies to be timeless, and we want people to really engage with the characters and find something that they can really relate to and emotionally connect with."

For directors Howard and Moore, it all started with their plucky protagonist, Judy (voiced by Ginnifer Goodwin). She's a driven and resilient young woman bunny who spends her time dreaming of the ZPD (Zootopia Police Department) and not the day her prince charming will come. Even when her father tries to talk down her ambition — "If you don’t try anything new, you’ll never fail," he tells her — she follows her own path, and not that of her 275 brothers and sisters. She's every bit as much a Disney heroine as any of those princesses, which was always the point.

"We didn't set out to make this rabbit a feminist hero, but the story just evolved that way," Moore said. "We wanted to portray this character as honestly and as genuine as we could. We see her go through a very difficult time in her life and watch as she comes out the other side as a better person. She's also extremely successful at what she does, and we wanted her to enjoy that success. ... Can't Judy just be Judy and be strong on her own? That was always our intent."

Judy's determination to accomplish her goals, regardless of what her doubters tell her, makes her one of Disney's most groundbreaking characters. In fact, Judy has a lot in common with one of Howard's earliest animation inspirations: Princess Ariel. In 1989, The Little Mermaid broke the mold for what a Disney movie, and a Disney princess, could be. Ariel was independent, free-willed, and wouldn't just settle down and live the life her father planned for her. Sound familiar?

"Ariel got me into animation," Howard said when asked about his early animation inspirations. "She was the first Disney heroine that really felt alive. She felt like a real young woman. There was something about the way that they were animating her, and there was something about what Ron [Clements] and John [Musker] did with that movie that really caught me. I saw it seven times in theaters. ... That was my spark."

Then, of course, there's Nick, the other half of the film's dynamic duo. He's undoubtedly an amalgamation of every Cool Guy character ever. He's sly, witty, and oh so charming. Nick may not break any new ground for the studio, but he's no Prince Charming either. In fact, the film does a decent job of exploring his own unique vulnerabilities as a predator who just wants to fit in.

"We knew we needed Nick to be snarky and kind of a wise-ass, but he had to have a warmth to him," Howard said. "Jason [Bateman] was perfect. He was our only choice. And people do just fall in love with Nick. The first thing I heard when I went to China was, 'Nick would be a perfect boyfriend.' And it goes back to that warmth and kindness. It also helps that there's a little bit of an edge, too."

As you can see in MTV News's exclusive deleted scene from Zootopia, Nick is also one glib entrepreneur:

Whether Nick is truly perfect boyfriend material has yet to be officially discussed by Howard and Moore, who both admit that they'd love to revisit the lush world of Zootopia for a potential sequel or series of short films. But they have been paying attention to the fandom. In many ways, Zootopia has found a second life on Tumblr, where impassioned fans can engage with the material Howard and Moore spent five years creating. After all, Zootopia is so much more than a movie; it's a world. And it's a space that gives fans ample room to play, create, and put their own spin on characters like Judy and Nick.

"Twitter and Tumblr and Facebook, it's so amazing because years ago, when I was growing up and watching movies, there was no way for us to interact with filmmakers at all," Howard said. "You could send a letter, and you'd never know if you were going to hear back or not. The fact that you can actually talk to people who made the movies, and for us to be able to talk to people who have seen the movies, it's kind of incredible. ... It's great to see that creativity, and it inspires us too. We'll see artwork online, and we'll go, 'Oh man, that would be great to do a mashup of these two worlds.' We're artists ourselves, so we rely on each other for inspiration."

"I love that fans feel comfortable enough to send us their artwork," added Moore. "If someone is taking the time to do a piece of artwork and address it to me and Byron, then I'm going to acknowledge it. When I was a kid, if I'd had access to the filmmakers and artists that I loved, that's what I wish they would have done for me. For artists, we're always looking for approval. We're putting our artwork out there, and saying, 'What do you think?' So I think it's really important that we respond to that stuff. That person could be an incredible filmmaker down the line, and that could be the moment that got them through a really tough time."

However, there is one point of contention among the fans and filmmakers: the nature of Judy and Nick's relationship. Shipping is an invaluable part of fandom culture, so it's not surprising that some fans would pair the film's two main characters together, but according to the directors, their relationship is left intentionally ambiguous. (Though they are definitely best friends. That's canon.)

"At the very end of the movie, it does feel like there could be a little bit more, but never did I think that it would turn into the shipping that it's become," Moore said. "It's so weird because half the fans are like, 'We love WildeHopps, and they need to get together and get married,' and then there's this other side that's like, 'No! They should not get together. Do male and female characters always have to get together at the end of every movie? Can't they just stay best friends?' I love the debate that's going on between the fans right now."

But Moore also acknowledges that this kind of debate is tricky to navigate for creators. The very nature of fan entitlement is murky, and it always ends with one side feeling left out.

"As filmmakers, it puts us in a spot," he said. "If we ever move forward with these characters and these stories, then that's a debate that we'll have to weigh in on. It will probably be the main issue we'll need to address. One side is going to be disappointed, and I don't know which side that is yet."

Regardless of where Nick and Judy go from here, it won't deter fans from exploring the sharp world Howard and Moore have created. When it comes to Zootopia, imitation isn't the sincerest form of flattery; it's creation.